Formaldehyde (H\(_2\) CO), a slightly asymmetric rotor molecule, is a ubiquitous molecule in interstellar clouds and exhibits a large number of millimetre and sub-millimetre transitions. Previous observations of H\(_2\) CO in various molecular environments indicate that it is a reliable tracer of physical conditions of dense gas (see [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}).
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